Method for preparing carbon articles.



PATENTED JUNEQQ, 1903.

' P. MON. BBNNIB. METHOD OF PREPARING CARBON ARTICLES.

APPLICATION FILED JULY 11, 1907.

I Lw e72 (0A7? @nrrp a m UNITED STAJFES PATENil. OFFICE.

METHOD OF PREPARING CARBON ARTICLES.

Application filed July 11. 190 Serial .1. 383,219.

lowing is a full, clear, and. exact description.

The object of the present invention is to provide an improvement in the art ol proparing carbon articles for machining.

M ore particularly, my invention is directed to preparing articles of hard, amorphous carbon for macl'iining, in such. manner that the difficulties attendant upon the machining prmiess will be eliminated while the carbons will retain such desirable qualities as they originally possess, particularly a high thermal resistantar and sullicient physical strength to withstand uses to which tlmy are subjected.

As is well known to those familiar with carbons, the ordinary article of amorphous carbon is diilic'ult to machine, especially where any delica cy of shape orl'orm is desired in the finished product, owing to the. hardness and the brittleness of the material upon which the tool operates. l have, however, discovered a method whereby a hard carbon article may be machined with accuracy and precision without losing that high thermal. resistance and strength which characterizes the hard carbon articles.

The invention may bebroadl y stated to comprise the process of locally softening the article'in those parts or paths in which the machining tool is to operate, without sutstantially allectin'g that portion of the material which is to form the finished article.

One method of practicing my invention may be understood from the specilicati on to follow, reference being had to the accompanyin drawings in which igure 1 diagraphieally illu trates the pro cedure ol forming a. screw thread upon a carbon core. .Fig. 2 diagraphieally illustrates the method of preparing a' carbon with a female screw thread. i

In practicing my invention, I prefer to cause an arc to play upon the surl'ace'ol. the hard amorphous carbon article from a stationary electrode and to manipulate the carbon article and present it to the stationary electrode in such manner that the are shall locally soften or graphitize the hard amor- Specification of Letters Patent.

Patented June 9, 1908.

phons :arbon m those port ions orparts which it is desired to remove. For example, in the drawings, where it is desired to form screw threads on the hard amorphous carbon blank A, I provide a stationary electrmle 13 connected with one terminal of a source of elec- 'tric current. (7, while lhe'carhon article. itself is rol'ineet'ed to the other terminal. Anv are l) is drawn between the stationary electrode and the carbon article which is preferably held in a movable socket or'chuck E of any sort capable of having thed sireil. path and rate of movement for presenting the carbon article to the electrmlc in such manner that the arc will be applied to those parts or portioits which it is desired to soften a 'l subsequently remove. 'lhus, by feeding the chuck or holder of the amorphous carbon article in the proper direction. and at the. required rate which may be controlled by a suitable lead-screw, or in any other'manner.

the graphitizing are may be. caused to follow the exact helical path of the groove which it is necessary to en t in the carbon in order to form the desired thread thereon. ii the value of the current be pro pcrly regulated the soften.- ing or grapl litiza-t ion will be sullicient and con- -lined to the desired localities. The. carbon may there-alter he put in a la he and the cut .ting tool controlled to remove the gra'phitized material. \a'hichmay readily be done, while the ren'iammg material, being still m a. hard amorphous condition, will possess substantially the original. high thermal resistance and physical strength which was present in the original article. it is to be seen, however, that it is within the. scope of my invention to have the cutting tool mounted in such manner that it shall operate immediately after and follow in the path of the electric arcso that the-operations of softening, or graphitizing, and machining are substantially simultaneous.

'lhe formationof the female screw thread shown in Fig. 2 does not 'dill'er in Ininciple, ofeourse, from the process outlincdin Fig. 1 it being merely necessary that the arrangel'IlG-Ili; of the parts he dillerent so as to correspond to the difference in. form of the article under treatment.

This process is not limited to the. formation of screw threads or to the production of any particular form, it being clear that the in ventio'nis applicable to any form which it dc. 'red to produce. I t is further obvious that it is not necessary to rely upon the elecfar tric are as the source of the heat necessary for softening or raphitization, as other means may be employed. For exam I le, the temperature required may be reac led by bringinq a carbon electrode into contact with the carbon article under treatment, at those points where it is desired to produce the efect, and passing a sufficiently heavy current therethrough.

Having thus described my invention, 1 claim: r r

1. The method of shaping hard carbon articles, which comprises the step of locally softening the articles in those )ortig'ms'whcrc the material is to be removed for the production of the finished form.

2. The method of shaping hard carbon articles which comprises as a step the local application of softening or graphitizing condi-' tions to the parts or portions of the article which it is desired to removeand removing such parts or )ortions.

3. lhe method of producing hard carbon shapes which consists in producing graphitiz ing conditions locallyupon a hard carbon article and removing the material thus graphitized.

4. The method of preparing hard carbon articles for machining, which ('UlllPllHfS'tll'itW- 5. The method of preparing hard carbon articles for shaping which comprises softening the portion to be cut away by high heat produced by the electric current.

6. The method of treating hard carbon articles by drawing an electric are from a fixed electrode to the carbon article to be prepared, and in moving said article so as to cause said are to follow and be substantially confined to that portion which it is necessary to remove.

7. A carbon article substantially consisting of hard carbon which has been locally softened in those parts or portions the removal of which is necessary for'the production of the finished form.

'8. An article of hard carbon which has been locally softened and machined, cut, or ground in the softened part.

In testimony whereof, I hereunto affix my signature in the presence of two witnesses.

PETER MON. BENNIE.

\Vitnesses MARY E. JAMES, .FmNors A. J. FITZGERALD. 

